8.38g 2NaO / 61.98g/mol = 0.135 mol 2NaO 0.135 mol 2NaO (6.02x10^23) = 0.814x10^23 you correct the scientific notation by moving the decimal's place and changing the exponent. 0.814x10^23 = 8.14x10^22
There are some crucial mistakes made in her word problems. 1. The problem at 36:49 says "If 9.00g of the compound contains 4.19x10^23 H atoms..." The problem is actually meant to say that "the compound of C, H, and Cl consists of 9.00g" or else her answer wouldn't make any sense. 2. The question about the blast furnace asks for "the percent purity of Fe2O3", but at the end, it was clearly meant to find the percent purity of Fe, because she uses the mole ratio to isolate Fe.
The iron cast question is shameful too. UCI should take this down. All these videos are full of mistakes. She’s not even putting proper labels on the dimensional analysis making it harder to follow.
The second question about a compound of c, h, and cl is atrocious. Shameful that a PhD lecturer would promote should horrible grammar and such a ridiculous question. A shame this has lasted on here since 2013. It's not easy to follow and just... bad.
